Re: [PATCH v5 06/15] ftrace: Use an opaque type for functions not callable from C

Kees Cook
2021-10-13T19:04:09Z

On Wed, Oct 13, 2021 at 11:16:49AM -0700, Sami Tolvanen wrote:
> With CONFIG_CFI_CLANG, the compiler changes function references to
> point to the CFI jump table. As ftrace_call, ftrace_regs_call, and
> mcount_call are not called by C code, but are trampolines injected
> as calls replacing the nops at the start of functions added by the
> compiler, use DECLARE_NOT_CALLED_FROM_C to declare them.
>
> Signed-off-by: Sami Tolvanen <samitolvanen@google.com>

Looks right to me...

Reviewed-by: Kees Cook <keescook@chromium.org>

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Kees Cook